Centerless grinder workpiece ejector



June 6 E. w. MARLEY 3,451,172

CENTERLESS GRINDER WORKPIECE EJECTOR Filed Sept. 12. 1966 INVENTOR 504mm n. M/MLA) ATTORNEYS United States Patent US. Cl. 51-103 5 Claims ABSTRACT OF THE DISCLOSURE A centerless grinder workpiece ejector hydrostatically operated by a control handle which displaces a piston in a master cylinder connected to a hydraulic cylinder, wherein the fluid displaced by the master cylinder displaces a slave piston connected to an ejector rod. The control handle may be actuated by the grinder infeed lever, or it may be actuated independently therefrom.

The present application relates to centerless grinder workpiece ejecting mechanisms, and more particularly to a workpiece ejector which is operable in conjunction with other controls of the machine or independently thereof.

Centerless grinding machines are usually provided with a workpiece ejector which is reciprocable within the grinding throat between the grinding wheel and regulating wheel when the wheels are relatively displaced apart from each other at the end of a grinding cycle. The ejector generally includes a rod adapted to push the finished workpiece from the top edge of the workpiece rest or shoe, from which it drops into a container or onto a conveyer, so as to free the grinding throat for another workpiece to be positioned between the wheels at the beginning of the next grinding cycle.

Workpiece ejectors for centerless grinding machines are generally operated under the dependence of the infeed lever that controls the relative displacement of the grinding and regulating wheels from an open throat position for ejection of the finished workpiece and loading of a new workpiece to a narrow throat position corresponding to the grinding operation. The ejector is generally hydraulically or pneumatically actuated by a solenoid valve controlled in turn by a limit switch, or the like, tied with the infeed mechanism. Consequently, the ejector can generally not be operated independently of the infeed control, and the ejector reciprocating velocity and the force of ejection of the workpiece can not generally be regulated in view of the preset pressure of the fluid in the hydraulic or pneumatic system.

The present invention provides for a workpiece ejector hydrostatically operated by means of a control handle which may be actuated independently from the infeed lever. Preferably, the control handle actuates a piston in a master cylinder which is adapted to displace a hydraulic fluid from said master cylinder to a slave cylinder wherein the fluid displaces a slave piston operatively connected to the ejector rod. Consequently, by proper choice of the control handle displacement, of the master piston stroke and area relatively to the area of the slave piston, the ejector speed, stroke and force may be easily and simply adapted to the type of work in process on the machine. In addition, the control handle is at all times urged to a position that causes the ejector rod to be retracted and the infeed lever is provided with means engaging the ejector control handle only during the last few degrees, as for example the last twenty degrees of the available swinging motion of the lever, such that the regulating and grinding wheels are already separated by a distance great- 3,451,172 Patented June 24, 1969 er than the normal grinding throat when the workpiece begins to be ejected from the top edge of the shoe or rest. Furthermore, the present invention provides for a workpiece ejector for a centerless grinding machine that can be easily installed on any grinding machines existing at the present on the market.

Those objects and advantages of the invention, and further other objects and advantages thereof, will become apparent to those skilled in the art when the following description of an example of a workpiece ejector mechanism for a centerless grinder according to the principles of the invention is read in conjunction with the accompanying drawings, wherein like numerals refer to like parts in the diverse views, and in which:

FIG. 1 is a schematic perspective view of a portion of a typical centerless grinding machine provided with a workpiece ejector mechanism according to the present invention; and

FIG. 2 is a schematic view substantially along line 22 of FIG. 1, and also showing the ejector control with portions broken away to show the internal construction in a schematic manner.

Referring now to the drawings, there is shown a portion of a centerless grinding machine bed 10 adapted to support, in the usual manner, a rotatable regulating wheel 12 and a rotatable grinding wheel 14 arranged with their axes of rotation substantially parallel to each other and enclosed respectively within housings 16 and 18. The two wheels 12 and 14 define therebetween a variable width grinding throat in which a workpiece 20 is normally situated, being supported therein by the top edge of a Workpiece rest or shoe 22. The infeed lever 24 is swingable or rockable angularly from an extreme position wherein the regulating wheel 12 and the grinding Wheel 14 are displaced toward each other to a finite preset distance defining a grinding throat of a predetermined width for grinding of the outer diameter surface of the workpiece 20, to another extreme position wherein the two wheels are displaced away from each other so as to open the grinding throat for ejection of the finished workpiece and loading of a new workpiece. Such normal working position of the infeed lever is in full lines at 24 in FIG. 1, the ejecting and loading position being shown in phantom line at 24 in the drawing.

Substantially with its axis aligned with the axis of the workpiece 20, an ejector rod 26 is disposed slidably through a bushing member 28 mounted on a bracket 30 fastened to the bed 10 of the grinding machine. Although shown as mounted in a fixed position in the drawing, it should be appreciated that the bracket 30 may alternately be adjustable in height and transverse positions so as to normally provide for alignment of the axis of the ejector rod 26 with respect to the axis of the workpiece.

A hydraulic slave cylinder 32 is mounted on bracket 30, the axis of the cylinder being substantially parallel to the axis of the ejector rod 26. The slave cylinder 32, as best seen in FIG. 2, contains a reciprocable piston 34 provided with a rod 36 adapted to project through the end of the cylinder and through the wall of the bracket and having a bent over portion 38 provided on its end with a ring 40 through which passes the body of the ejector rod 26. The ring 40 and the ejector rod 26 are adjustably fastened by means such as set screw 42. In this manner, the distance separating the end 44 of the ejector rod 26 when the piston rod 34 in the retracted position, shown in full lines in FIG. 2, from the rear face of the workpiece 20 may be adjustably set for varied lengths of workpieces.

A conduit 46 places the face of the piston 34 opposite to the face on which is mounted rod 36 in fluid communication with the interior of a hydraulic master cylinder 48. Within the master cylinder is disposed, as

best seen in FIG. 2, a reciprocable piston 50 displaceable by way of a control handle 52. The mechanical interconnection between control handle 52 and piston 50 may consist of any convenient arrangement, an example thereof being shown in the drawings which consists of the lower end of handle 52 being adjustably mounted upon the end of a transverse short shaft 54, journalled in opposed walls of the cylinder housing, by way of clamping cap 56 and bolts 58. Shaft 54 is adapted to angularly displace a lever 60 mounted thereon, the end of which is pivotally connected to a face of piston 50 by means of link 62.

In this manner, when handle 52 occupies the position indicated in full lines in FIG. 1, piston 50 occupies the position indicated in full lines in FIG. 2, this position of the handle being the one caused by the urging of biasing means such as spring 66 having one end attached to the handle and the other end attached to housing 16. When piston 50 occupies the position shown in full line in FIG. 2, the master cylinder 48 is filled with fluid, slave cylinder 32 is empty, and slave cylinder piston 34 occupies the position indicated in full lines in the drawing, thus retracting the ejector rod from within the working throat between the regulating and grinding wheels 12 and 14.

The infeed lever 24 is provided on its upper end with a cross bar 64 adapted to engage lever 52 when the infeed lever is displaced to its extreme clockwise position whereby the working throat of the grinding machine is open as a result of the regulating and grinding wheels being displaced away from each other. During the final portion of the swing of infeed lever 24, cross bar 64 engages lever 52 and causes it to be displaced in a clockwise direction to the position indicated in phantom lines at 52' in the drawing, piston 50 in master cylinder 48 being displaced to the position shown in phantom lines at 50'. Consequently, hydraulic fluid is expelled from the master cylinder 48 through conduit 46 into the slave cylinder 32, thus displacing slave piston 34 from the position shown in full lines to the position shown in phantom lines at 34. The ejector rod 26 is consequently displaced to the portion shown in phantom lines at 26', thus ejecting the finished workpiece 20 to the position shown in phantom lines at 20' where it is no longer supported by the edge of the workpiece rest or shoe 22 and is caused to drop.

Infeed lever 24 is then manually brought back to a counterclockwise position that causes cross bar 64 to cease from engaging control handle 52. Control handle 52 is returned under the action of spring 66 to a position that retracts master piston 50 to the position shown in full lines, thus drawing back fluid from slave cylinder 32 into master cylinder 48 and causing slave piston 34 to be returned to the position shown in full lines in the drawing. In this manner, ejector rod 26 is retracted from within the grinding throat between the regulating and grinding wheels 12 and 14, and the grinding throat is now ready to accept another workpiece being loaded therein. The infeed lever 24 is subsequently manually returned to its extreme counterclockwise position which operates the infeed mechanism such that the grinding throat closes to its normal work width.

The infeed mechanism operating the relative displacement of the regulating and grinding wheels 12 and 14 with respect to each other has usually some backlash so that when the infeed lever 24 is displaced from its extreme clockwise position, whereby the grinding throat is open and the ejector rod 26 is extended between the regulating and grinding wheels, the first few degrees of swing of the infeed lever in a counterclockwise direction causes the ejector rod to retract before the mechanism backlash is taken up to the point that the regulating and grinding wheels begin to move toward each other. The invention thus takes to advantage the otherwise undesirable backlash in the infeed mechanism in such a manner that the ejector rod is retracted from the grinding throat when the wheels are still separated by a distance greater than the distance providing the normal grinding throat, such that a new workpiece may be loaded between the two wheels as soon as the ejector is retracted. The infeed lever 24 and the control handle 52 are angularly disposed around their respective fulcrum relatively to each other such that the cross bar 64 of the infeed lever 24 engages the control handle 52 during the last 20 degrees of the clockwise swinging motion of the infeed lever, as previously mentioned.

It will also be appreciated that by changing the areas of the respective master and slave pistons 50 and 34 diverse ejection strokes, speeds and forces may be obtained.

It will be understood by those skilled in the art that various modifications and improvements in the details of the arrangement described and illustrated for illustrative purpose only may be made within the scope of the invention as enunciated in the appended claims.

What is claimed as new is:

1. In a centerless grinding machine having a grinding wheel and a regulating wheel spaced apart to define a grinding throat therebetween for grinding a workpiece there supported by the top edge of a workpiece shoe and an infeed lever adapted to control the relative displacement of said wheels toward each other and away from each other, a workpiece ejector comprising:

an ejector rod reciprocable along an axis substantially coincident with the axis of said workpiece;

a slave hydraulic cylinder;

a reciprocable piston in said slave cylinder;

an adjustable mechanical connection between said piston and ejector rod for causing reciprocation of said rod as a result of reciprocation of said piston;

a master hydraulic cylinder in fluid communication with said slave cylinder;

a reciprocable piston in said master cylinder for displacing a volume of hydraulic fluid from said master cylinder to said slave cylinder so as to cause the piston in said slave cylinder to reciprocate;

a handle mechanically interconnected with the piston in said master cylinder so as to convert angular motion of said handle into reciprocable motion of said piston;

a spring bias on said handle for normally urging said handle to a position that retracts said piston in said master cylinder for causing the piston in said slave cylinder to occupy a position whereby said ejector rod is retracted from the grinding throat during grinding of a workpiece; and

means on the infeed lever for engaging said handle for a portion of the end swing of said lever that causes the regulating and the grinding wheels to be relatively displaced from each other for causing said handle to advance the piston in said master cylinder to bydraulically displace the piston in said slave cylinder to a position that advances the ejector rod into said grinding throat for ejecting a workpiece.

2. The centerless grinding machine of claim 1 wherein:

the ejector rod is reciprocable through a bushing having its axis substantially parallel to the axis of said slave cylinder; and

the piston in said slave cylinder has a projecting rod having a bent over end adapted to be adjustably fastened to said ejector rod.

3. The centerless grinding machine of claim 2 wherein said means on the infeed lever engages said handle for about the last 20 of swing of said lever.

4. In a centerless grinding machine having a grinding wheel and a regulating wheel spaced apart to define a grinding throat therebetween for grinding a workpiece supported by the top edge of a workpiece shoe and an infeed handle adapted to control the relative displacement 5 of said wheels toward each other and away from each other, a workpiece ejector comprising:

an ejector rod reciprocable along an axis substantially coincident with the axis of said workpiece; hydraulic means for extending said ejector rod through said grinding throat; a manual control for said hydraulic means, said manual control comprising:

a handle normally urged to a position that retracts said ejector rod from said grinding throat; and

means dependent from the infeed lever for engaging said handle only when said lever occupies a position that displaces said wheels away from each other, for hydraulically causing extension of said ejector rod.

5. The centerless grinding machine of claim 4 wherein said hydraulic means comprises:

a slave cylinder;

21 hydrostatically displaceable piston in said slave cylinder operatively connected to said ejector rod; and wherein said manual control comprises:

a master cylinder;

a piston in said master cylinder;

means operatively connecting said handle to said piston; and

conduit means for transfering hydraulic fluid from said master cylinder to said slave cylinder.

References Cited UNITED STATES PATENTS 1,575,558 3/1926 Einstein et al. 51-215X 1,864,578 6/1932 Binns 51103 2,603,916 7/1952 Price 51-215 X 2,801,499 8/1957 Jones 51103 2,921,414 1/1960 Garberding 51103 LESTER M. SWINGLE, Primary Examiner.

U. S. Cl. X.R. 51215 

